Approach for Hemolymph Collection and Biochemical Profiling of Invasive Callinectes sapidus: Methodology and Physiological Assessment

The blue crab, Callinectes sapidus, is an invasive species in the Mediterranean Sea, where it has gained particular attention since 2023 due to its negative ecological and economic impacts. This study aimed to define a standardized method for hemolymph collection and biochemical analysis in male blue crabs from the northern Adriatic Sea, providing data on their physiological status. Hemolymph was collected following a standardized protocol. Preliminary validation tests showed good recovery, stability and linearity results for biochemical analytes, showing no significant analytical interference due to hemolymph pigmentation. Then, key biochemical variables, including glucose, calcium, magnesium, triglyceride, urea, uric acid, aspartate transaminase, gamma-glutamyl transferase, phosphate, potassium, sodium, chloride and total protein, were analyzed. The results revealed considerable variability in the biochemical profiles of the sampled individuals, consistent with the natural heterogeneity expected in a field-collected, mixed-molt cohort, while overall indicating a generally consistent euryhalinity, a good physiological status. The study underscores the importance of standardized protocols for hemolymph analysis in blue crab, contributing to the understanding of its physiology and invasive success.